Exploring mechanisms of spontaneous functional connectivity in MEG:/nHow delayed network interactions lead to structured amplitude/nenvelopes of band-pass filtered oscillations
Spontaneous (or resting-state) brain activity has attracted a growing body of neuroimaging research over the last/ndecades.Whole-brain networkmodels have proved helpful to investigate the source of slow(b0.1 Hz) correlated/nhemodynamic fluctuations revealed in fMRI during rest. However, the mechanis...
| Autores: | , , , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repositorio: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:10230/23081 |
| Acceso en línea: | http://hdl.handle.net/10230/23081 http://dx.doi.org/10.1016/j.neuroimage.2013.11.047 |
| Access Level: | acceso abierto |
| Palabra clave: | Resting state MEG Oscillations Network Kuramoto Modeling Structural connectivity Functional connectivity |
| Sumario: | Spontaneous (or resting-state) brain activity has attracted a growing body of neuroimaging research over the last/ndecades.Whole-brain networkmodels have proved helpful to investigate the source of slow(b0.1 Hz) correlated/nhemodynamic fluctuations revealed in fMRI during rest. However, the mechanisms mediating resting-state/nlong-distance correlations and the relationship with the faster neural activity remain unclear. Novel insights/ncoming from MEG studies have shown that the amplitude envelopes of alpha- and beta-frequency oscillations/n(8–30 Hz) display similar correlation patterns as the fMRI signals./nIn thiswork, we combine experimental and theoreticalwork to investigate the mechanisms of spontaneousMEG/nfunctional connectivity. Using a simple model of coupled oscillators adapted to incorporate realisticwhole-brain/nconnectivity and conduction delays, we explore how slow and structured amplitude envelopes of band-pass/nfiltered signals – fairly reproducing MEG data collected from 10 healthy subjects at rest – are generated spontaneously/nin the space-time structure of the brain network./nOur simulation results show that the large-scale neuroanatomical connectivity provides an optimal network/nstructure to support a regimewith metastable synchronization. In this regime, different subsystems may temporarily/nsynchronize at reduced collective frequencies (falling in the 8–30 Hz range due to the delays) while the/nglobal system never fully synchronizes. This mechanism modulates the frequency of the oscillators on a slow/ntime-scale (b0.1 Hz) leading to structured amplitude fluctuations of band-pass filtered signals. Taken overall,/nour results reveal that the structured amplitude envelope fluctuations observed in resting-state MEG data may/noriginate from spontaneous synchronization mechanisms naturally occurring in the space-time structure of/nthe brain. |
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